Designation as sensitive area or vulnerable zone to pollution from urban waste waters of a marine reserve

The Italian legislation DL 152 of 11 May 1999 has absorbed the Council Directive of 12 December 1991 (91/676/EEC) concerning the protection of coastal waters against pollution, through the designation of sensitive areas and vulnerable zones. As consequence, urban discharges for areas with a number of inhabitants >10.000 should be treated using more restrictive limits to obtain a better quality. In a previous work we have carried out a study in order to define the critical dispersion conditions of contaminants from the sewage of the town of Acitrezza into the "Isola dei Ciclopi" marine reserve. With the present project, according to the new italian legislation, experimental measurements and numerical simulations have been used to define a number of diffusion coefficients that cause the most unfavourable conditions for the contamination of the sea-water: the main aim was to establish if the zone we are monitoring can be designated as a sensitive area or vulnerable zone to pollution. Particular attention is paid on the risk of eutrophication of the coastal waters caused by the increasing of the amount of compounds that alterate the concentration of nutritive substances, producing an undesirable disturbance to the balance of organisms present in the water.